Windows “Snapshots” are totally different, they are just files copied from one location to another. Snapshots on the filesystem level are totally different from that, They mark blocks on your harddisk as immutable and will only change a copy of them and pretend the immutable copy has been overwritten, but still keep a reference to it.
You can then either drop those old references or roll back to them.
On BTRFS or ZFS I can create a snapshot worth 500 GiB of data in split seconds, and then copy this snapshot over to my backup system. And the nice thing is, the system can stay active in that time.
Lets consider a postgres or mysql database, usually if you just do a cp of the data folder and move use it as backup, then the database itself will probably be corrupted due to the serialised copy. eg. the index file has been copied after the table itself, and the index has been changed since then.
The snapshout of BTRFS and ZFS though is atomic. All files are fixed in time. If you snapshot and copy this snapshot as a backup, you can restart a database using that snapshot, and it will recover from it similar to how it would recover from a power outage, as all files still are coherent in their state.